1. Field of the Invention
The present invention is directed to improvements in bypass oil refining devices of the type which are connected to internal combustion engines. More particularly, the present invention is directed to a bypass oil refining device which has improved performance characteristics regarding the flow of engine oil through the device and regarding the operation of a heating element which distills water and volatile fuel vapors out of the oil.
2. Brief Description of the Prior Art
Bypass oil refining devices for internal combustion engines have been known in the art for a long time. More particularly, bypass oil refining devices of the type to which the present invention pertains are often incorporated as "add-on devices" in automobiles and trucks. The principal function of such bypass oil refining devices is to remove volatile liquid contaminants, such as water and fuel (gasoline or diesel fuel) from the engine oil. This is a function which is not at all performed by the conventional oil filters included in virtually all internal combustion engine driven vehicles.
In addition to a heating mechanism which causes water and fuel vapors to distill out of the engine oil, the bypass oil refining devices usually also incorporate a substantially conventional oil filter to remove solid particles from the oil. In this respect the bypass oil refining devices provide an additional oil filter to supplement the particle and sludge removing action of the conventional oil filter of the vehicle.
In order to accomplish the above-summarized functions, the bypass oil refining devices are fluidly connected to the crankcase or oil line of the engine at a point where oil pressure is relatively large. The oil continuously flows from the crankcase into the bypass device. From the bypass oil refining device the purified oil returns to the crankcase through another fluid line. Thus, in accordance with the prior art, bypass oil refining devices have a mechanical filtering medium (such as a disposable filter cartridge containing cotton waste and excelsior), and a heating element for rapidly heating the oil to sufficiently high temperature so as to boil out, as vapors, a substantial amount of the water and fuel contaminants of the oil.
A specific embodiment of a bypass oil refining device of the above-summarized type is described in U.S. Pat. No. 4,349,438. In the device of this prior art patent the mechanical filter cartridge is separated from a vaporization chamber by a vaporization plate which has only a single narrow conduit or nozzle to permit flow of oil from the filter cartridge into the vaporization chamber. An electrical heating element is disposed in the vaporization chamber and is energized by the battery of the car or truck (or boat or the like) which is driven by the internal combustion engine. Water and fuel vapors, which are distilled out of the oil in the vaporization chamber, are released into the environment through a vent having a check valve. Oil is supplied to the device under pressure by a line connecting an oil inlet of the device with a "high pressure" point in the vehicle's oil system or crankcase.
Principal disadvantages of the above-summarized prior art bypass oil refining devices include the following. Carbonaceous material forms relatively rapidly during operation of the device and it deposits on the surface of the heating element. The carbon or carbon-like deposit on the heating element insulates it from the oil, and thereby reduces its effectiveness to transfer heat to the oil. In some extreme situations the ability of the heating element to transfer heat may be reduced by the deposited carbon to such extent that water and fuel vapors are no longer effectively distilled out of the oil in the vaporization chamber.
Another disadvantage of the device described in U.S. Pat. No. 4,349,438 is that as the vehicle moves, especially on a rough road, the liquid oil accumulated in the vaporization chamber is subjected to a surging and slushing action. When the oil covers the nozzle leading from the mechanical filter cartridge to the vaporization chamber (due to the undulating, surging, or slushing action caused by movement of the vehicle), then there is no longer a narrow stream of oil coming into direct contact with the heating element. Consequently, effectiveness of heating, and distillation of oil and fuel vapors from the oil in the vaporization chamber is diminished.
Still further, under certain operating conditions the oil pressure in the crankcase is sufficiently high so as to result in undesirably high flow rate through the bypass refining device, and in undesirably high oil pressure in the vaporization chamber. When the vaporization chamber becomes filled with oil, excess oil may be released into the environment through the vent and check valve. Loss of engine oil in this manner is, of course, highly undesirable.
Even during normal operation of the bypass oil refining device (when the vent and check valve of the prior art bypass oil refining devices function properly and release only water and fuel vapors) the release of water and particulary fuel vapors into the environment is undesirable for environmental reasons.
In light of the foregoing, there exists a need in the prior art for an improved bypass oil refining device for internal combustion engines, primarily for trucks and automobiles, which overcomes the above-summarized disadvantages of the prior art. The present invention provides such an improved bypass oil refining device.